A liquid crystal display device of the type having a liquid crystal driving integrated circuit mounted on a liquid crystal display substrate (generally known as a chip-on-glass liquid crystal display device--hereinafter referred to as the "COG liquid crystal display device") has the problem that it requires a large press-contact area for connecting input electrodes to a flexible printed circuit (hereinafter abbreviated FPC) in order to input power and signals to the liquid crystal driving integrated circuit.
In-view of this, a lateral-lead type COG liquid crystal display device has been proposed in which input terminals of a liquid crystal driving integrated circuit are arranged along a shorter side of a substantially rectangular integrated circuit chip, with an FPC press-contact area provided on the shorter side of the integrated circuit, and electrical conductors leading from electrodes on a liquid crystal display substrate are routed to the shorter side for connection to the input terminals.
FIG. 1 is a schematic diagram showing an input portion of the COG liquid crystal display device having a liquid crystal driving integrated circuit 720 mounted on a liquid crystal display substrate 723.
In the figure, an input electrode A 701 is an electrode for inputting a signal to the liquid crystal driving integrated circuit 720 via an input terminal A 711; an input electrode B 702 is an electrode for inputting a signal to the liquid crystal driving integrated circuit 720 via an input terminal B 712; an input electrode C 703 is an electrode for inputting a signal to the liquid crystal driving integrated circuit 720 via an input terminal C 713; an input electrode D 704 is an electrode for inputting a signal to the liquid crystal driving integrated circuit 720 via an input terminal D 714; and an input electrode E 705 is an electrode for inputting a signal to the liquid crystal driving integrated circuit 720 via an input terminal E 715.
A VDD electrode 707 is an electrode for supplying a high input voltage to the liquid crystal driving integrated circuit 720 via a VDD terminal 716; a VSS electrode 708 is an electrode for supplying a low input voltage to the liquid crystal driving integrated circuit 720 via a VSS terminal 717; and a VM electrode 709 is an electrode for supplying an intermediate input voltage to the liquid crystal driving integrated circuit 720 via a VM terminal 718.
Here, the intermediate input voltage refers to an intermediate-level voltage potential prepared separately from the high and low input voltages. An output terminal array 721 is provided to drive the liquid crystal. A press-contact area 724 provides a space for connecting the input electrodes to the FPC.
In the above-described lateral-lead type liquid crystal driving integrated circuit, since a large number of signal terminals and power supply terminals are arranged along one of the shorter sides of the liquid crystal driving integrated circuit, the arrangement of electrical conductors brought out for connection to the input electrodes and power supply electrodes becomes complex, and the conductors must be made thin because of the limited space. This increases the resistance of the signal electrodes and power supply electrodes, posing various problems when driving the liquid crystal.
Furthermore, when using more than one lateral-lead type liquid crystal driving integrated circuit, as many FPC press-contact areas have to be provided as there are liquid crystal driving integrated circuits.